View source for Astronomy:Lacerta

{{Short description|Constellation in the northern celestial hemisphere}}
{{Infobox constellation|
name = Lacerta |
abbreviation = Lac |
genitive = Lacertae |
pronounce = {{IPAc-en|l|æ|ˈ|k|ɜːr|t|ə}},<br>genitive {{IPAc-en|l|æ|ˈ|k|ɜːr|t|i}} |
symbolism = the [[Biology:Lizard|Lizard]] |
RA = {{RA|22.5}} |
dec= {{DEC|+45}} |
family = Perseus |
quadrant = NQ4 |
areatotal = 201 |
arearank = 68th |
numbermainstars = 5 |
numberbfstars = 17 |
numberstarsplanets = 12 |
numberbrightstars = 0 |
numbernearbystars = 1 |
brighteststarname = α Lac |
starmagnitude = 3.76 |
neareststarname = [[Astronomy:EV Lacertae|EV Lacertae]] |
stardistancely = 16.47 |
stardistancepc = 5.05 |
numbermessierobjects = 0 |
meteorshowers = |
bordering = [[Astronomy:Andromeda (constellation)|Andromeda]]<br /> [[Astronomy:Cassiopeia (constellation)|Cassiopeia]]<br /> [[Astronomy:Cepheus (constellation)|Cepheus]]<br /> [[Astronomy:Cygnus (constellation)|Cygnus]]<br /> [[Astronomy:Pegasus (constellation)|Pegasus]] |
latmax = [[Earth:North Pole|90]] |
latmin = 40 |
month = October |
notes=}}
'''Lacerta''' is one of the 88 modern [[Astronomy:Constellation|constellation]]s defined by the [[Organization:International Astronomical Union|International Astronomical Union]]. Its name is [[Social:Latin|Latin]] for [[Biology:Lizard|lizard]]. A small, faint constellation, it was defined in 1687 by the astronomer [[Biography:Johannes Hevelius|Johannes Hevelius]]. Its brightest stars form a "W" shape similar to that of [[Astronomy:Cassiopeia (constellation)|Cassiopeia]], and it is thus sometimes referred to as 'Little Cassiopeia'. It is located between [[Astronomy:Cygnus (constellation)|Cygnus]], Cassiopeia and [[Astronomy:Andromeda (constellation)|Andromeda]] on the northern [[Celestial sphere|celestial sphere]]. The northern part lies on the [[Astronomy:Milky Way|Milky Way]].

==Notable features==
[[Image:LacertaCC.jpg|thumb|left|200px|The constellation Lacerta as it can be seen by the naked eye.]]
Lacerta is typical of [[Astronomy:Milky Way|Milky Way]] constellations: no bright [[Astronomy:Galaxy|galaxies]], nor [[Astronomy:Globular cluster|globular cluster]]s, but instead [[Astronomy:Open cluster|open cluster]]s, for example [[Astronomy:NGC 7243|NGC 7243]], the faint [[Astronomy:Planetary nebula|planetary nebula]] IC 5217 and quite a few [[Astronomy:Double star|double star]]s. It also contains the prototypic [[Astronomy:Blazar|blazar]] [[Astronomy:BL Lacertae|BL Lacertae]].
Lacerta contains no [[Biography:Charles Messier|Messier]] [[Astronomy:Messier object|objects]].

===Stars===
[[Astronomy:Alpha Lacertae|Alpha Lacertae]] is a blue-white hued main-sequence star of magnitude 3.8, 102 light-years from Earth. It has a [[Astronomy:Stellar classification|spectral type]] of A1&nbsp;V<ref name=Cowley1969>{{citation | display-authors=1
 | last1=Cowley | first1=A. | last2=Cowley | first2=C.
 | last3=Jaschek | first3=M. | last4=Jaschek | first4=C.
 | title=A study of the bright A stars. I. A catalogue of spectral classifications
 | journal=Astronomical Journal | postscript=.
 | volume=74 | pages=375–406 | date=April 1969
 | doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}</ref> and is an optical [[Astronomy:Double star|double star]]. [[Astronomy:Beta Lacertae|Beta Lacertae]] is far dimmer, a [[Astronomy:Yellow giant|yellow giant]] of magnitude 4.4, 170 light-years from Earth.{{sfn|Ridpath|Tirion|2008|pp=164-165}}

Roe 47 is a multiple star consisting of five components (magnitudes 5.8, 9.8, 10.1, 9.4, 9.8).

[[Astronomy:ADS 16402|ADS 16402]] is a [[Astronomy:Binary star|binary star]] system in Lacerta, around which a planet orbits with some unusual properties.<ref>[https://www.nytimes.com/2006/09/15/science/space/15planet.html?ref=spaceandcosmos Puzzling Puffy Planet, Less Dense Than Cork, Is Discovered - New York Times]</ref> The [[Astronomy:Jupiter|Jupiter]]-sized planet exhibits an unexpectedly low density, about the same as cork. This planet is dubbed HAT P-1.

[[Astronomy:EV Lacertae|EV Lacertae]] is a rapidly spinning magnitude 10 [[Astronomy:Red dwarf|red dwarf]] with a strong [[Physics:Magnetic field|magnetic field]]. It is a [[Astronomy:Flare star|flare star]] that can emit powerful [[Astronomy:Stellar flare|flares]] potentially visible to the naked eye, thousands of times more energetic than any from Earth's sun.

HD 215441 (22h 44m.2 / +55° 35') is known as '''Babcock's Magnetic Star'''. Source: ''Sky Catalogue 2000.0 Volume 2: Double Stars, Variable Stars and Nonstellar Objects'', page xlv, chapter ''Glossary of Selected Astronomical Names''.

===Deep-sky objects===
[[Astronomy:NGC 7243|NGC 7243]] is an [[Astronomy:Open cluster|open cluster]] 2500 light-years from Earth, visible in small amateur telescopes. It has a few dozen "scattered" stars, the brightest of which are of the 8th magnitude.{{sfn|Ridpath|Tirion|2008|pp=164-165}}

[[Astronomy:BL Lacertae|BL Lacertae]] is the prototype of the [[Astronomy:BL Lacertae object|BL Lacertae object]]s, which appear to be dim variable stars but are actually the variable nuclei of [[Astronomy:Elliptical galaxy|elliptical galaxies]]; they are similar to [[Astronomy:Quasar|quasar]]s.{{sfn|Ridpath|Tirion|2008|pp=164-165}} It lent its name to a whole type of celestial objects, the [[Astronomy:BL Lacertae object|BL Lacertae object]]s (a subtype of [[Astronomy:Blazar|blazar]]). The object varies irregularly between magnitudes 14 and 17 over a few days.

==History==
[[File:Sidney Hall - Urania's Mirror - Lacerta, Cygnus, Lyra, Vulpecula and Anser.jpg|thumb|upright=1.25|right|Lacerta can be seen on the left of this 1825 star map from ''[[Astronomy:Urania's Mirror|Urania's Mirror]]'']]
Centred on a region of the sky without apparently bright stars, Lacerta was apparently not regarded as a constellation by ancient Western astronomers. [[Biography:Johannes Hevelius|Johannes Hevelius]] created the constellation in 1687 and initially named it "Stellio" (the stellion), a lizard with star-like dorsal spots found along the Mediterranean coast.{{sfn|Allen|1899|p=251}}

Other Europeans who sought to name this new constellation{{dubious|date=February 2014}} included Augustin Royer, who created [[Astronomy:Sceptrum et Manus Iustitiae|Sceptrum et Manus Iustitiae]] (the Hand of Justice and Sceptre) to honor Louis XIV in 1670, and Johann Elert Bode, who created Frederici Honores (Frederick's Glory) to honor [[History:Frederick the Great|Frederick the Great]] in 1787. Both Sceptrum and Frederici Honores are now [[Astronomy:Former constellations|obsolete]], while Lacerta still survives.{{sfn|Ridpath|Tirion|2008|pp=164-165}}

==Equivalents==
Although not included in ancient star charts of Europe and the Near East, the stars of Lacerta, along with some in the eastern portion of Cygnus, were coincidentally combined by early Chinese astronomers into their "[[Astronomy:Flying serpent (asterism)|Flying serpent]]".{{sfn|Allen|1899|p=251}}  Similarly, the Chumash people of {{wipe|California}} call this part of the sky 'Lizard' and include it in multiple stories.{{Citation needed|date=November 2011}}

==Namesakes==
USS Lacerta (AKA-29) was an attack cargo ship in the United States navy named after the constellation.

== See also ==
* Lacerta (Chinese astronomy)

== References ==
{{reflist}}

==Sources==
{{refbegin}}
* {{cite book| first1 = Richard H.| last1 = Allen|  date = 1899| title = Star-names and their meaning| url = https://archive.org/stream/starnamesandthe00allegoog#page/n98/mode/2up/search/lacerta| location = New York| publisher = Stechert}}
* {{cite book| title = Stars and Planets: The Most Complete Guide to the Stars, Planets, Galaxies, and the Solar System| series = Princeton Field Guides| last1 = Ridpath| first1 = Ian
{{refend}}

==External links==
{{Commons|Lacerta (constellation)}}
* [http://www.allthesky.com/constellations/lacerta/ The Deep Photographic Guide to the Constellations: Lacerta]
*[http://www.ianridpath.com/startales/lacerta.html Star Tales – Lacerta]
*Weasner's Mighty ETX Site, [http://www.weasner.com/etx/ref_guides/lacerta.html ''GO TO LACERTA''] (a constellation guide for amateur astronomers)

{{Stars of Lacerta}}
{{navconstel}}
{{ConstellationsByHevelius}}
{{Sky|22|30|00|+|45|00|00|10}}

{{DEFAULTSORT:Lacerta, Constellation}}
[[Category:Northern constellations]]

{{Sourceattribution|Lacerta}}